Thermally Activated Dissipation in Bi2.2Sr2Ca0.8Cu2O8+

A new dissipation behavior is reported in superconducting Bi2.2Sr2Ca0.8Cu2O8+ for all temperatures below Tc and all magnetic fields exceeding Hc1. The current-independent electrical resistivity is thermally activated and can be described by an Arrhenius law with a single prefactor and a magnetic-field- and orientation-dependent activation energy U0(H,). This behavior is markedly different from past observations and will be discussed in terms of flux creep and flux flow. This thermally activated behavior implies a finite resistance at all temperatures and all fields exceeding Hc1 determined by the activation energy as the only parameter.